1. Technical Field
The invention concerns a microscopic hole or a set of microscopic holes (pinholes), the number of these holes and/or their size being able to be modified easily. Such a set of pinholes is intended to be used for various applications in optics, in particular in confocal microscopy.
2. State of the Art
In confocal microscopy use is usually made of two types of pinhole:
holes of fixed size: to modify the size of a hole, it is necessary to replace it with another. Typically several pinholes can be mounted on a wheel having a position corresponding to the use of each of these holes. The movement of the wheel must be very precise.
holes of variable size: functioning on the principle of the iris diaphragm, they require at least three blades which form a hole by crossing one another and are expensive because of the relative complexity of the mechanism.
Conventionally, confocal microscopy systems require the use of a single pinhole. For example, the first embodiment of French patent application number 0103860 of 22 Mar. 2001, as well as the microscope described in FIG. 3 of the U.S. Pat. No. 5,978,095 or the microscope described in the U.S. Pat. No. 5,162,941.
Other confocal microscopy systems require the use of an array of pinholes. For example, the microscopes described by FIG. 1 of U.S. Pat. No. 5,239,178 or FIG. 3 in the U.S. Pat. No. 5,978,095, or the Nipkow disk systems.
In certain embodiments of a microscope such as the one described in French patent number 0103860 of 22 Mar. 2001; an array of pinholes must be positioned with great precision, which is difficult using a simple technique consisting of exchanging the whole of the array. When “single” pinholes are simply exchanged, as on certain single-point confocal microscopes, their precise positioning is also difficult. In addition, the systems for exchanging arrays of pinholes are necessarily bulky, since their size is the sum of the sizes of each array able to be exchanged.
In the case of microscopes using an array of pinholes, the size and density of the holes cannot usually be modified. However, this modification is desirable in order to adapt the size of the holes to the wavelength being studied. U.S. Pat. No. 6,002,509 affords a solution to this problem in the case of a Nipkow disk microscope. However, this solution requires the replacement of the array of holes with an array of reflective points. When the technique used consists of using reflective points produced by a multilayer treatment, each wavelength corresponds to a given size and density of the reflective points. It is then not possible to modify the size or density of the holes of the hole with a given wavelength, and the number of different sizes of holes is limited by the performance of the multilayer treatment. When the technique used consists of introducing several concentric rings on the Nipkow disk, a movement of the disk, which is not very practical, is necessary, and the size of the disk rapidly becomes excessive. The technique is difficult to adapt to systems using a fixed array of pinholes.